(((((((((((lmg)))))))))))))
I think a huge part of the depression is that it makes it impossible for us to stop thinking about certain things. When my depression gets really bad, I sleep all the time, not so much because of low energy as that the only time I get any peace inside my head is when I'm unconscious. I know what you mean when you say you're drowning.
My suggestion is to try to distract yourself. If you catch yourself thinking negatively or about things that you don't want to, play mindgames to distract yourself -- it sounds silly but I will focus on counting by twos or trying to recite the alphabet backwards in my head, and it distracts me from all the things I don't want to be thinking about at that moment.
take care